/// <summary>
/// Ensures that a CoordinateSequence forms a valid ring,
/// returning a new closed sequence of the correct length if required.
/// If the input sequence is already a valid ring, it is returned
/// without modification.
/// If the input sequence is too short or is not closed,
/// it is extended with one or more copies of the start point.
/// </summary>
/// <param name="fact">The CoordinateSequenceFactory to use to create the new sequence</param>
/// <param name="seq">The sequence to test</param>
/// <returns>The original sequence, if it was a valid ring, or a new sequence which is valid.</returns>
public static CoordinateSequence EnsureValidRing(CoordinateSequenceFactory fact, CoordinateSequence seq)
{
int n = seq.Count;
// empty sequence is valid
if (n == 0)
{
return(seq);
}
// too short - make a new one
if (n <= 3)
{
return(CreateClosedRing(fact, seq, 4));
}
bool isClosed = seq.GetOrdinate(0, 0) == seq.GetOrdinate(n - 1, 0) &&
seq.GetOrdinate(0, 1) == seq.GetOrdinate(n - 1, 1);
if (isClosed)
{
return(seq);
}
// make a new closed ring
return(CreateClosedRing(fact, seq, n + 1));
}
private static CoordinateSequence CreateClosedRing(CoordinateSequenceFactory fact, CoordinateSequence seq, int size)
{
var newseq = fact.Create(size, seq.Dimension);
int n = seq.Count;
Copy(seq, 0, newseq, 0, n);
// fill remaining coordinates with start point
for (int i = n; i < size; i++)
{
Copy(seq, 0, newseq, i, 1);
}
return(newseq);
}
public static CoordinateSequence Extend(CoordinateSequenceFactory fact, CoordinateSequence seq, int size)
{
var newseq = fact.Create(size, seq.Ordinates);
int n = seq.Count;
Copy(seq, 0, newseq, 0, n);
// fill remaining coordinates with end point, if it exists
if (n > 0)
{
for (int i = n; i < size; i++)
{
Copy(seq, n - 1, newseq, i, 1);
}
}
return(newseq);
}
/// <summary>
/// Constructs a GeometryFactory that generates Geometries having the given
/// CoordinateSequence implementation, a double-precision floating PrecisionModel and a
/// spatial-reference ID of 0.
/// </summary>
public GeometryFactory(CoordinateSequenceFactory coordinateSequenceFactory) :
this(new PrecisionModel(), 0, coordinateSequenceFactory)
{
}
/// <summary>
/// Constructs a GeometryFactory that generates Geometries having the given
/// PrecisionModel, spatial-reference ID, and CoordinateSequence implementation.
/// </summary>
public GeometryFactory(PrecisionModel precisionModel, int srid, CoordinateSequenceFactory coordinateSequenceFactory)
{
_precisionModel = precisionModel;
_coordinateSequenceFactory = coordinateSequenceFactory;
_srid = srid;
}
public OgcCompliantGeometryFactory(PrecisionModel pm, int srid, CoordinateSequenceFactory factory)
: base(pm, srid, factory)
{
}
/// <summary>
/// Creates an instance of this class using the default
/// values for <see cref="GeometryFactory.SRID"/>,
/// <see cref="GeometryFactory.PrecisionModel"/>,
/// but the specified <paramref name="factory"/>.
/// </summary>
public OgcCompliantGeometryFactory(CoordinateSequenceFactory factory)
: base(factory)
{
}
